Militia

Towers are good cheap fortifications. They take some time to build, and time to topple. They also power defense of your own territory with two powerful defensive technologies.

Militia technologies give you the power to change Citizens into light foot units. If you have extra Citizens left over from a large construction project or workers obsoleted by an efficient economy, you can hand them rifles and send them abroad with your army.

If you're invaded, change Citizens into Militia to save your cities. No matter where or when you deploy them, you can change them back into workers after the fight.

Towers from around the world throughout the game: